search_messages

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the burden and does real work: it discloses the return scope (envelope data, not bodies), result ordering (newest first), and a security boundary about treating message content as untrusted external data that cannot authorize tool use. It omits pagination behavior (how to page past the limit) and any auth/account prerequisites, so it is strong but not complete.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose and ordering are front-loaded in the first sentence, and the get_message pointer follows immediately. The security paragraph is boilerplate-heavy and noticeably longer than the functional content, but each sentence still serves a purpose.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema, the description usefully characterizes the return as envelope-only and ordered newest first, and warns about untrusted content. It does not explain pagination beyond the schema's limit parameter or how results are shaped, which is a gap for an 11-parameter search tool, but the essentials for correct invocation are present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 55%, so the baseline is 3. The description adds no meaning to the 11 parameters—it does not clarify to/from/subject matching semantics, what unseen/flagged filter in combination, or how text search interacts with header fields. The schema documents roughly half (text, limit, since, before, folder, account), leaving the description silent rather than compensating.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ("Search messages in a folder"), adds scope (folder) and ordering (newest first), and explicitly distinguishes itself from get_message by noting it returns envelope data only. An agent can tell it apart from siblings like get_message or search_index without opening a schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly routes the agent: use get_message for the message body, implying this tool is for discovery/listing rather than retrieval. No explicit when-not conditions (e.g., when to use search_index vs search_messages) or prerequisites are given, so it falls short of a full 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.